xref: /openbmc/linux/drivers/char/tpm/tpm_atmel.h (revision 8edd49ce)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Copyright (C) 2005 IBM Corporation
4  *
5  * Authors:
6  * Kylene Hall <kjhall@us.ibm.com>
7  *
8  * Maintained by: <tpmdd-devel@lists.sourceforge.net>
9  *
10  * Device driver for TCG/TCPA TPM (trusted platform module).
11  * Specifications at www.trustedcomputinggroup.org
12  *
13  * These difference are required on power because the device must be
14  * discovered through the device tree and iomap must be used to get
15  * around the need for holes in the io_page_mask.  This does not happen
16  * automatically because the tpm is not a normal pci device and lives
17  * under the root node.
18  */
19 
20 struct tpm_atmel_priv {
21 	int region_size;
22 	int have_region;
23 	unsigned long base;
24 	void __iomem *iobase;
25 };
26 
27 #ifdef CONFIG_PPC64
28 
29 #include <linux/of.h>
30 
31 #define atmel_getb(priv, offset) readb(priv->iobase + offset)
32 #define atmel_putb(val, priv, offset) writeb(val, priv->iobase + offset)
33 #define atmel_request_region request_mem_region
34 #define atmel_release_region release_mem_region
35 
atmel_put_base_addr(void __iomem * iobase)36 static inline void atmel_put_base_addr(void __iomem *iobase)
37 {
38 	iounmap(iobase);
39 }
40 
atmel_get_base_addr(unsigned long * base,int * region_size)41 static void __iomem * atmel_get_base_addr(unsigned long *base, int *region_size)
42 {
43 	struct device_node *dn;
44 	unsigned long address, size;
45 	const unsigned int *reg;
46 	int reglen;
47 	int naddrc;
48 	int nsizec;
49 
50 	dn = of_find_node_by_name(NULL, "tpm");
51 
52 	if (!dn)
53 		return NULL;
54 
55 	if (!of_device_is_compatible(dn, "AT97SC3201")) {
56 		of_node_put(dn);
57 		return NULL;
58 	}
59 
60 	reg = of_get_property(dn, "reg", &reglen);
61 	naddrc = of_n_addr_cells(dn);
62 	nsizec = of_n_size_cells(dn);
63 
64 	of_node_put(dn);
65 
66 
67 	if (naddrc == 2)
68 		address = ((unsigned long) reg[0] << 32) | reg[1];
69 	else
70 		address = reg[0];
71 
72 	if (nsizec == 2)
73 		size =
74 		    ((unsigned long) reg[naddrc] << 32) | reg[naddrc + 1];
75 	else
76 		size = reg[naddrc];
77 
78 	*base = address;
79 	*region_size = size;
80 	return ioremap(*base, *region_size);
81 }
82 #else
83 #define atmel_getb(chip, offset) inb(atmel_get_priv(chip)->base + offset)
84 #define atmel_putb(val, chip, offset) \
85 	outb(val, atmel_get_priv(chip)->base + offset)
86 #define atmel_request_region request_region
87 #define atmel_release_region release_region
88 /* Atmel definitions */
89 enum tpm_atmel_addr {
90 	TPM_ATMEL_BASE_ADDR_LO = 0x08,
91 	TPM_ATMEL_BASE_ADDR_HI = 0x09
92 };
93 
tpm_read_index(int base,int index)94 static inline int tpm_read_index(int base, int index)
95 {
96 	outb(index, base);
97 	return inb(base+1) & 0xFF;
98 }
99 
100 /* Verify this is a 1.1 Atmel TPM */
atmel_verify_tpm11(void)101 static int atmel_verify_tpm11(void)
102 {
103 
104 	/* verify that it is an Atmel part */
105 	if (tpm_read_index(TPM_ADDR, 4) != 'A' ||
106 	    tpm_read_index(TPM_ADDR, 5) != 'T' ||
107 	    tpm_read_index(TPM_ADDR, 6) != 'M' ||
108 	    tpm_read_index(TPM_ADDR, 7) != 'L')
109 		return 1;
110 
111 	/* query chip for its version number */
112 	if (tpm_read_index(TPM_ADDR, 0x00) != 1 ||
113 	    tpm_read_index(TPM_ADDR, 0x01) != 1)
114 		return 1;
115 
116 	/* This is an atmel supported part */
117 	return 0;
118 }
119 
atmel_put_base_addr(void __iomem * iobase)120 static inline void atmel_put_base_addr(void __iomem *iobase)
121 {
122 }
123 
124 /* Determine where to talk to device */
atmel_get_base_addr(unsigned long * base,int * region_size)125 static void __iomem * atmel_get_base_addr(unsigned long *base, int *region_size)
126 {
127 	int lo, hi;
128 
129 	if (atmel_verify_tpm11() != 0)
130 		return NULL;
131 
132 	lo = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_LO);
133 	hi = tpm_read_index(TPM_ADDR, TPM_ATMEL_BASE_ADDR_HI);
134 
135 	*base = (hi << 8) | lo;
136 	*region_size = 2;
137 
138 	return ioport_map(*base, *region_size);
139 }
140 #endif
141